Starting DSOs AP equipment advice

[Mqrko]

Hi,

I've been doing astrophotography for a few months now and taking pictures of the milky way is not enough for me anymore.
I tried taking pictures of Lovejoy comet...I wish I had better gear at that time :( ... I want more now :)
I'm currently using a Nikon D800. In the future, I might switch to ccd cameras if I want better quality.

Do I have to switch to Canon for AP ? It seems to be the favorite for AP.

So I've been searching for quite some time now and also looked at Forrest Tanaka videos on youtube which are very usefull. I want to take pictures of DSOs (90%) but it's a bonus if I can do planetary photography (10%)

I would like something easy to carry. I don't mind if it's a bit heavy as long as it's not a 2 mans job and fits in the SUV. Easy to setup.

For the mounts:
- Sky-Watcher AZ-EQ6 GT or NEQ6 Pro. Any difference ?
- Atlas Pro EQ/AZ
- CGEM 925 or CGEM 925 Pro. Any difference ?
- CGEM DX 1100 EdgeHD

The NEQ6 Pro and AZ-EQ6 GT (same question for CGEM 925 and CGEM 925 Pro), are they the same ? Looks like the same spec but different names.
I'm looking at ozscopes as they are currently on sales and Bintel.

I'm sceptical about picking Celestron because the review are not that great and the customer service is bad.

I picked these mounts because I think it can be useful in the future if I buy a second OTA.
I also checked the G11 but the setup can be frustrating so I took it out of the list. It's also heavier and a lot more expensive than the others.

I'm still very confused about choosing between refractor or SCT. I want the objects I'm photographing to fill the frame of my camera.
SCTs have longer focal length so I guessed that is the type I have to choose but I saw different opinions saying that it's not meant for DSOs AP.
We can use a focal reducer which makes it faster, right ? So where is the problem ?

I don't want to crop my pictures. A little bit is okay but I won't crop 50% of the picture for example.

For refractors, it would be 100 to 150mm APO. Too expensive above.
For SCT, the SCT C9.25 or C11. I read that the 11" can be too heavy (not really sure about that) and the 9.25" is the sweet spot for the mounts I listed.

If I buy a telescope (e.g SCT 9.25), does it always come with a mount or is it sold separately ? I could save some money to spend elsewhere. I won't need the extra mount as I will buy another one.
Or I can buy, for example, the CGEM 925 which comes with a mount already and save a little bit.

What else do I need to buy ? Let me know if I miss something or add too much :)
- tripod ?
- autoguider
- guider scope. Some people use a refractor as a guider scope. Why doing this ? More accurate ? But you add more weight to the mount.
- power supply
- focuser ?
- T ring + T ring adapter for dslr

I haven't looked at all the extras I need for AP because I'm focused on picking the mount + OTA first.
The budget is about $10k but I can be flexible. I think it's already a very good start.
I will also be printing the pictures in big for family, friends, me.

Hope this thread can also be useful for other people :)

Thank you,

Cheers,
Mqrko.

[lazjen]

I don't have enough experience/knowledge to answer your questions, but I can add some info here for you to consider.

Do you use a computer to connect to the camera to take your photos? If not, you might want to consider doing so and to hook it up with the rest of the system (mount, autoguiding). A search on this site should turn up possible software you can use that can control a nikon (if any).

G11: I won't dispute it being heavy (still 1 person manageable and portable) or expensive, but frustrating setup? Not too much to me at least and it's the only mount that I've ever used. I found it also is pretty easy to hook up with the computer as well.

[Mqrko]

Yes, I will connect the camera to the laptop.

About the G11, its what I read from various forums. The bad ones mostly.

I also like the concept of the EQMOD.

[raymo]

Many DSOs will nowhere near fill the frame, no matter what scope you use, [ at prime focus], they are simply too small, so you either crop
greatly, or use eyepiece projection,[generally inferior results], or
don't image them at all. It is not realistic to fill the frame without
cropping much of the time. Conversely, some DSOs are too big to
fit in the frame with any scope, and must be imaged with a camera
and lens piggy backed on the scope. No one scope is really good for
every target. Most imagers have at least two scopes, and many have more than that. The one scope that comes nearest to doing what you want is the excellent Celestron 9.25 SCT, but even with a focal reducer it still has a great focal length. For filling the frame without cropping, most of the time, a refractor is not suitable, unless you get one with an
f ratio of 9 or more, which becomes a large unwieldy beast at apertures
over around 110mm.
raymo

[rustigsmed]

I'd suggest looking at astro targets you like on the net, and seeing what type of telescope was used to achieve the result. that may help you decide whether a SCT, refractor, newt or RC will suit you. then attend an astro society or star party to see the size of equipment.

there is no one scope fits all (even with a focal reducer - or a barlow). my own view was that 10" and up Newtonians are kind of allrounders as they are in the middle, good enough aperture for planets and giving a medium field of view for DSO. I'd also love a big RC for galaxies and a takahashi for wide field nebs :D

[Amaranthus]

The Skywatcher AZ-EQ6 (and the Orion Atlas Pro EQ/AZ - same design) has both alt-az mode and equatorial. The NEQ6 only has EQ. The former also has a belt drive and dual encoders. It's a better mount all round, but more expensive.

[rat156]

Hi Marko,

You ask many questions but I shall only answer a couple, but ask another in return.

Cropping pictures is inevitable, the DSOs aren't all the same size and your focal length is fixed. Also you need to do some research on oversampling, essentially you need to match the pixel size to focal length, or vice-versa. After many years and many scopes, I have settled for a fast Newtonian scope. Faster is better, believe me. Even though there is a thing called the f-ratio myth, practical experience says faster scope = better data, but conversely smaller images. Guiding at long focal lengths on anything but a premium mount can cause much frustration, it has made many a budding astrophotographer give up.

My question to you is how much are you prepared to spend?

Buy the best mount you can afford, I have a Paramount MX, but have had a G11. The G11 was good, the PMX is better. Paramount have a smaller mount, but I don't know how good it is. Don't be scared to buy secondhand, especially from here.

Cheers
Stuart

[Mqrko]

Thank you so much for your help. I'll reply to everybody in this post.

I'm willing to spend so no worries on this side.

I understand that I'm not able to fill the frame for most of the DSOs. Since it's inevitable, I'll crop then, no worries. I thought all the pictures I saw weren't and couldn't see much info in the description or exif.

I'm still reading articles about sampling optimization. So i'm sorry if I say something wrong.

I matched the focal length with my camera using this website (http://www.astro.shoregalaxy.com/dslr_calc.htm).

For the D800:
- Sensor width = 35.9
- Sensor height = 24
- Resolution width = 7360

If I put 450mm focal length, it's enough for andromeda galaxy. It also gives me 2.23 arcsecond/pixel, which is good, right ? A 80mm refractor is the best for this.
I would also be able to take pictures of all the big objects like M7, M8, M25, M33, M34, M42, M45, etc...

If I increase the focal length, I will be oversampling for anything more than 1000mm (?)
Do I need to be between 1-3 arcsecond/pixel ? I would then need another camera to match the telescope.

I think using 2 telescopes would be too heavy for the mounts I listed previously so the EQ8, G11 are more suited for the load. I'm more interested in EQ8 for EQMOD. The price of the Paramount MX is too much for me. I could spend the money elsewhere with $10k difference.

I haven't considered the newtonian because of coma and it looks BIG.
Ritchey Chretien and Astrograph are the same thing, right ? The pictures I saw look nicer and I like the effect of the diffraction spikes. I would consider buying one if it fits in the car with all the equipment.
I picked SCT, because it's easier to transport, but I can change my opinion. I'm not in a rush.
Is there a big difference between this and SCT for visual purposes ?

[dannat]

i wouldnt be moving to canon but either sticking with nikon or going for astro camera - something lke qhy8

the mounts you suggested will be fine

-if you want start with an ed80 [secondhand] that way when you get better you can either get a CAT or Newt to increase aperture..you won't lose much money on reselling the ed80 if you buy s/hand

[kosh]

You don't have to use them both at the same time. You pick your target, and use the scope depending on whether you want a larger image scale for the smaller objects, or a wider view for the extended DSO's like large nebulae. I have an 8" F4 newt for my little CCD for things like galaxies and small nebula ( think M20), and a short refractor for things like the Horsehead and Flame nebula, Eta Carina etc.

Are you going to continue with the Nikon, or will you move to an astro CCD?
CCD sensors are often smaller than DLSR's which will change your FOV and scale again.

[rat156]

Hi Marko,

If you are prepared to spend, then buy the best mount you can afford, believe me, or don't, but ask any of the astrophotographers on the forum and you'll get the same answer. Mount, mount, mount. The EQ8 and G11 are good mounts, but the difference between them and a Paramount or Astrophysics mount is like chalk and cheese.

You'll need a field flattener for using the D800 with an ED80, even then the image will be vignetted quite badly.

Your calculations are out as well, you need 0.5-1.5"/pixel (depending on your seeing, but better to oversample a bit than under sample (square stars)) see this website for more details
http://www.stanmooreastro.com/pixel_size.htm (the final sentence)
http://www.stanmooreastro.com/SamplingFratioMyth.htm

So for your camera a FL of about 800mm would be fine. This means a nice f/4 imaging Newtonian would be a great choice, Bintel have a 200 mm f/4 (1.2"/pixel) up to 300 mm f/4 (1200 mm FL, 0.8"/pixel) imaging Newtonian. This type of scope will probably require a corrector, but enquire around, maybe someone has some experience with them.

Astrograph is a generic term for a scope which the primary function is to take pictures, think of it as a scope optimised for astrophotography rather than visual. As such most RCs are astrographs, but not all astrographs are RCs.

Pretty much any SCT will have a FL which is too long for your camera, they are also plagued by dew formation on the corrector, the correction of which can cause other problems. Similar problems for big refractors. Newtonian scopes are far less susceptible to dew problems.

So, my advice...

You have already decided to keep the D800, so that sets your pixel size. Next research which scope best suits and decide on the FL. This sets the total mass that the mount will have to lug around. Then decide on the actual scope you want, a cheaper Chinese brand, or perhaps a more expensive European or US made scope. Then you will know how much is left of your budget to spend on a mount, buy the best one you can afford.

Cheers
Stuart

[rmuhlack]

Because the D800 is full frame, I think you should seriously consider an alternative camera with a smaller sensor - either a CCD or a DSLR with an APS-C crop sensor. The reason being that most telescopes are not designed for imaging with a full frame sensor - the "corrected field" of most flatteners / coma correctors is only up to APS-C, meaning that beyond this the image will not be properly corrected for coma, spherical aberation etc. Furthermore a 2" focuser is too narrow for a full frame sensor, and will result in significant vignetting (as Stuart mentioned above).
I am fairly sure that none of the correctors available for a SCT will provide a corrected, unvignetted image if used with a Full Frame camera. Telescopes which are available locally which accomodate full frame are refractors like takahashi FSQ/TOA. Televue 101is, or the Orion Optics AG newtonians. These are all VERY expensive. However if you can go with a crop sensor, your options will expand considerably - ED80, newtonians with a Baader MPCC corrector, SCT scopes etc.

[alocky]

The D800 is very well matched to the FSQ106, but as others have pointed out that sensor is very large and there aren't many other scopes that will work well with it. Having said that, there are second hand FSQs about, and I think it's worth it. Also , the D800 works well with some of the older f2.8 D series telephotos as in these links:
http://www.astrobin.com/62545/B/
http://www.astrobin.com/47941/
Here's a couple of D800/FSQ106 shots:
http://www.astrobin.com/24974/
http://www.astrobin.com/20395/B/
So don't let anyone tell you a Nikon can't do AP...
cheers,
Andrew

[killswitch]

Hi Marko

I was in the same shoes as you over a year ago. I went with the AZ-EQ6 and an ED100 and it has kept me going since and probably for years to come.

The D800 barely has any vignetting (w/ a true 2" T-adapter) and the field curvature hasnt bothered me since it gets cropped out anyway. You can also just set it to 1.2x or 5:4 Crop Mode to get rid of the edges.

[Camelopardalis]

Marko, don't get hung up on not cropping anything. It's inevitable with anything less than perfect framing on the ideal sized objects. In reality, objects come in all shapes and sizes. This is also why one single scope isn't going to cover your bases, because of the focal length giving different FOV regardless of what camera you use.

But don't undermount. If you go for a small to medium refractor then AZ-EQ6. For anything bigger than a C8 you probably want the EQ8.

Picking a long focal length instrument as a first step is an interesting challenge. There's a lot of satisfaction to be had from subjects in the 400-800mm focal length range. Reducers for the C11 Edge series should give you a pretty good image across the sensor, but you're looking at about 2m focal length and a lot of weight, not to mention cost. Currently there's no reducer for the C9.25 Edge, so you're stuck at f/10 and 2350mm.

[Mqrko]

I'm looking at this article about the sampling : http://www.astropix.com/wp/2011/03/01/sampling-and-pixel-size/
How do I determine the seeing ? Is it different for each DSO ?

In your experience, do you often use 2 telescopes or you pick one telescope and stick with it for the whole night ?
I also want to use my telescopes for visual, just a quick look. nothing special.

I think it will be better for me to get a modified canon DSLR. It's cheaper than buying a CCD camera.
Is it better to buy the telescope, then find a camera matching the telescope or the opposite ?

If I want to save time tweaking the mount, is it better picking a higher end mount ?
I also looked at the mach1GTO and 1100GTO, very expensive :/
How does it compare to the EQ8 or G11 ? is the difference obvious ? Can I have the same picture quality with a little bit of work ?

I also read about the Hyperstar which can be used with SCTs that are compatible. Is this a good alternative to RC ?

Where can I find second hand equipment (I found Astromart so far) ? It's a lot more cheaper to buy in the USA.
How much is the delivery cost and customs approximately ?
Concerning the warranty, if something bad happens, do I have to send it back to the country it comes from ?

[photosinferno]

Marko,
Its all about the Mount…any telescope no matter how much you spend will under perform if the mount is not up to tracking/or carrying the weight you ask of it.
Bear in mind it's not just the weight of the Scope and the camera,it all the extras like guide scope counterweights etc….
The EQ8 you mentioned or the G11 are good choices, I would debate if the EQ8 can be 'thrown' in the back of an SUV mind….

Just my thoughts…..
John

[Mqrko]

do you mean that the EQ8 is too fragile to be put in the boot of the car ?

[Amaranthus]

Too heavy/bulky.

[photosinferno]

As Barry said.
Mobile imagers normally choose something in the weight (to lift/carry) range of the HEQ-5 Pro. However it has no-where near the the 'load' capacity of the EQ-8.

John

[Mqrko]

oh yes that's right. G11 is a lot less heavy.

EQ8 is 25kg
G11 is 16kg
HEQ5 Pro is 10kg

I can handle 16kg, it's not much compared to the HEQ5 Pro, not sure about carrying 25kg...so I think I've done my choice on the mount :)

[glend]

I use an NEQ6 as my mobile imaging mount and have no problems with it. Don't forget the rated capacity of any mount is for visual use. If your imaging you want to keep the load to 2/3rds to 3/4s of the rated capacity. I run with about 15kg on my mount for imaging and its very good - but take the time to establish a firm tripod base for each leg, pavers are good if you can carry three with you.

[Mqrko]

For the G11, the maximum payload is 50kg so I think it's more than enough.

[RickS]

Unless you have a top tier mount (e.g. Astro-Physics or Bisque Paramount) it would be unwise to go anywhere near the maximum payload spec if you're imaging.

[Mqrko]

Yes, I'll limit the load to 30kg max.
I'll start with a short refractor first then get something bigger when I have enough experience.

Usually, what do people get in the beginning ? an 80mm refractor ?

[rat156]

Hi Marko,

Seeing is location dependant, this is another reason why APers will travel. It depends on many things, your surroundings, the weather and the jet stream.

Typically most people spend several nights per target, sometimes you can get away with a target in a single night, but I'm used to shooting LRGB or narrowband, OSC may be different.

WRT your camera choice, a modded DSLR may be cheaper but undoubtedly a CCD camera is better for most targets. I've just had my CCD in for repair and was using my DSLR, I have to say CCD is the way to go, again find a 2nd hand CCD and it'll be cheaper than a DSLR and if you find you don't like AP, then selling it should not be a problem. Your camera choice will influence your scope choice and vice versa, look at a package, know what matches what and hunt around.

I have used my PMX away from home, it's best described as transportable rather than portable. I used a 4WD to transport it and the scope, but with a smaller scope a normal sedan would work. The AP1200 GTO that's on IIS classifieds at the moment is a steal, I considered buying it as a trade up from the PMX, then flogging the PMX, but I would class the 1200 GTO as a permanent mount, wouldn't think of going bush with it. Picture quality depends on many things, not having to "tweak" your mount just takes one variable out of the equation, I, personally think a premium mount is worth every cent.

Hyperstar SC's suffer from all the dewing problems of normal SCs and have a huge central obstruction. I've not seen that many great pictures produced with one, compared to other designs (Newtonian, RC etc).

Secondhand gear is cheaper in the US. You'll find a good selection here though, and not have to deal with customs. Astronomy gear does not attract a duty, but is subject to GST on the price including freight, so be careful that bargain may not be. I have just posted on IIS about a good experience with a local supplier.

Usually AP scopes are not that good for visual, SCTs are an exception though. I have a 14" goto Dobsonian mounted Newtonian for visual stuff.

HTH.

Cheers
Stuart

[sil]

Marko, I suggest you learn to use your d800 and processing involved in astrophotography. I do just fine with my D800e from a tripod (no problems with comets), and before my stroke was getting great galaxies/nebula with camera on my cgem dx. Never connected it to any of my scopes, just camera and lens (what do you think a telescope is anyway??). If it makes you feel better to throw money on gear go ahead, I dont think the gear is the limitation.

[Mqrko]

I usually go to Blackheath mount or other lookouts in blue mountains for 1 night. I unfortunately don't have the time to do several nights :/
what are the seeings for these places ?

I think the best thing to do is to keep my d800 to start with, until I'm more experienced.
I can deal with the vignetting since I have to crop the picture.

The T-adapter and T-ring cost nothing so I prefer spending the money on those instead of buying another DSLR which is about $300 plus the extras accessories.

So far I've made this list. Is everything coherent ?
- Orion ED80T CF APO.
It comes with 2" dual-speed Crayford focuser. Does it worth it to change it to a Moonlite focuser ? Reviews on CN are quite good for the dual speed Crayford.
- Losmandy G11 G.
Do I need to upgrade the worm gear to Ovision worm ?
- Nikon T-Ring
- 2" T-adapter (any brand will do ?)
- TSOAG9
- SX Lodestar or SX Lodestar X2 ?
Which field flattener would you suggest for the scope ?
Is there any cable I have to add or everything is included ?

I'll try to find these items second hand.

Do I also have to calculate the spacing between the eyepiece and my sensor ?

To protect the equipment against dew, basically, what I need is a dew shield for the scope, autoguider and the dslr. And a dew controller to control the temperature of the dew shield. Is it correct ?

[Amaranthus]

The ED80T CF focuser is excellent and doesn't need swapping out. I use the TRF-2008 field flattener with it, which takes the FL to 384mm. Spacing is 56mm.

[Mqrko]

Is the 56mm spacing also for a Full Frame DSLR ?

I need to calculate the distance of
focal reducer + OAG + 2" t adapter + t ring
then add some spacers to find the optimum focus

is it correct ?

[rustigsmed]

Hi Marko,

the spacing refers to the sensor spacing not the front of the camera - for eg I know with canons the sensor to "start of the camera" is 44mm which only leaves ~11mm to squeeze in a coma corrector (which requires spacing 55-58mm similar to the field flattener) with OAG between them.

Which meant using a 0mm bayonet eg http://www.teleskop-express.de/shop/product_info.php/info/p6527_TS-Optic-ultrashort-Adapter-from-M48-to-Canon-EOS-EF-Bayonet---only-1-mm-optical-l.html note that this link is for a canon I don't know if they exist or not for Nikons.

So you may need a field flattener with longer spacing to get around it - I don't have a refractor so not sure if they are common.

cheers

rusty

[Mqrko]

the sensor spacing of the d800 is 46.5mm which leaves me 9.5mm if I use 56mm spacing. It's just enough to put the TSOAG9 and I have 0.5mm left.

I found an adapter for Nikon but the website doesn't provide details on the spacing.
http://www.teleskop-express.de/shop/product_info.php?products_id=3629#z ubehoer

http://gerrygibbscamerawarehouse.com.au/telescopes-discount-prices/t-mount-camera-adapters/t2-ring-m48---nikon-f

Other solution:
WO AFR-IV gives me more range to play with at 66-86mm spacing but someone else in the forum had issue with it so I'm not very confident buying it. Anybody else has experience with it ?
http://www.iceinspace.com.au/forum/showthread.php?t=45822
http://www.iankingimaging.com/show_product.php?id=927

WO Flattener 6 has 70.5mm spacing. I haven't found any reviews.
http://www.williamoptics.com/accessories/flattener6A_spec.php

Just to be sure, this is the correct setup, right ?
Telescope (ED80) -> 2" focuser (2" dual-speed Crayford) -> Focal reducer -> Spacing if required -> TSOAG9 -> M48 bayonnet Nikon -> D800

[rustigsmed]

Hi Marko,

You need the TSOAG9 with M48 attachment, just so you know I have a feeling the TSOAG9 actually equals 11mm when attached to adaptors/connectors - but you are best off emailing Thomas from the TS for advice on if it would work or not.

Let us know how you get on :thumbsup:

Cheers

[Mqrko]

The description says:

-- Length to the 2" terminal: 9mm
-- Length to the M48x0.75 thread for screwed adaptations: 11.2mm

So I guess, I have to do the calculation using the 11.2mm ?

It's not going to work if it's 11.2. I have to find something else :)

[Mqrko]

I sent an email to TS, waiting for their answer.

Having a ccd camera would solve everything, right ?

I'm thinking about the QSI 683 which comes with everything, all in one product so I don't need to scratch my head.
Atik 383L is a bit more expensive since it's not sold as a package.
SBIG ST-8300M, I haven't found review on the integrated auto guiding camera.

[rustigsmed]

ccd cameras generally have a much shorter distance to sensor so spacing to correctors aren't as tight.

I used to use a MPCC (coma corrector) that had the 55-58mm spacing but now use a RCCI (91.5mm) to allow the use of filters in the imaging train.

[Mqrko]

Yes, depending on the answer, I'll decide if I go for CCD or not.

I think I will buy the g11 and the ed80 first so I can play with it a little bit. I also need it for the next blood moon :)

[Mqrko]

I received the confirmation there is no working nikon adaptor for my setup and TS suggested me to get a finder scope 8x50 instead.

[rustigsmed]

that is unlucky, so you're not going to consider a different flattener with longer spacing?

[Mqrko]

I considered the wo flattener 4 but there are not many reviews on this one unfortunately :/

I decided to get the qsi 683, it's an easier solution :)

[rustigsmed]

WO have a pretty good reputation (generally) but if you've got the budget to go straight to the qsi 683 then why not :thumbsup: